title: Shape from sound: evidence for a shape operator in the lateral occipital cortex.
abstract: A recent view of cortical functional specialization suggests that the primary organizing principle of the cortex is based on task requirements, rather than sensory modality. Consistent with this view, recent evidence suggests that a region of the lateral occipitotemporal cortex (LO) may process object shape information regardless of the modality of sensory input. There is considerable evidence that area LO is involved in processing visual and haptic shape information. However, sound can also carry acoustic cues to an object's shape, for example, when a sound is produced by an object's impact with a surface. Thus, the current study used auditory stimuli that were created from recordings of objects impacting a hard surface to test the hypothesis that area LO is also involved in auditory shape processing. The objects were of two shapes, rods and balls, and of two materials, metal and wood. Subjects were required to categorize the impact sounds in one of three tasks, (1) by the shape of the object while ignoring material, (2) by the material of the object while ignoring shape, or (3) by using all the information available. Area LO was more strongly recruited when subjects discriminated impact sounds based on the shape of the object that made them, compared to when subjects discriminated those same sounds based on material. The current findings suggest that activation in area LO is shape selective regardless of sensory input modality, and are consistent with an emerging theory of perceptual functional specialization of the brain that is task-based rather than sensory modality-based.
authors.affiliation: Department of Psychological and Brain Sciences, Indiana University, United States. thwjames@indiana.edu
authors.forename: Thomas W
authors.initials: TW
authors.lastname: James
authors.forename: Ryan A
authors.initials: RA
authors.lastname: Stevenson
authors.forename: Sunah
authors.initials: S
authors.lastname: Kim
authors.forename: Ross M
authors.initials: RM
authors.lastname: Vanderklok
authors.forename: Karin Harman
authors.initials: KH
authors.lastname: James
mesh_terms: D000161:Acoustic Stimulation; D001307:Auditory Perception / Q000502:physiology*; D001931:Brain Mapping; D005260:Female; D005556:Form Perception / Q000502:physiology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008670:Metals; D009778:Occipital Lobe / Q000502:physiology*; D011597:Psychomotor Performance / Q000502:physiology; D021641:Recognition, Psychology / Q000502:physiology; D014796:Visual Perception / Q000502:physiology; D014934:Wood; D055815:Young Adult
chemical_list: D008670:Metals